Process for producing alkali metal



1-50. Asa further feature of this Patented Aug. 17, 1937 acaasaz PATENT OFFICE PROCESS FOR PRODUCING ALKALI METAL UREAS Ralph A. Jacobson, Wilmington, D'el., assignor to E. I. du Pont de Nemours & Company, Wilmington, D'el.,,a corporation of Delaware No Drawing. Application April 9, 1935, Serial No. 15,425

14 Claims.

This invention relates to urea derivatives and more. particularly to an improved method for producing alkali metal derivatives of urea and incompletely substituted ureas. By the latter term is meant; a urea still having at least one lic sodium is added gradually to a solution of a gram mol. of urea in liquid ammonia and left therein for a short time, and the ammonia subsequently removed by distillation, evaporation, filtration, or the like, a reactive white solid, havgoing the correct analysis for monosodium urea,

is obtained.

,In, like manner, I have" found that incompletely'substituted ureas, ,(such particularly as contain aryl, acyl, alkyl, aralkyl and like groups) may be similarly treatedby alkali metals to produce alkali metal substituted ureas. For example, alkyl ureas, such as methyl and ethyl urea, alkylene ureas such as ethylene urea, acyl ureas such as formyl'urea and diacetyl urea, may be utilized according to this invention. Thus, if a gram atom of metallic sodium or other alkali metal is added to a liquid ammonia solution of a'gram mol. of a monoacylated urea, "a monosodium or a monoalkali metalacyl urea is ob,-

tained upon removal of theammonia. In general,

any substituted urea which still contains replaceable hydrogen directly attached to nitrogen may .be utilized in accordance with the present invention, or, stated in another way, any urea may 40 be utilized which has at least one amido hydrogen atom. 7

Although the methodof this invention is generally practicalat ordinary pressures and temperatures below the boiling point of liquid am- .-.245 monia, more elevated temperatures and pressures may be employed advantageously for speeding up the reaction. Thus,.ifor example, pressures ranging up to 400 atmospheres and more 'may be used, if desired,

invention; I have found that byvarying the ratio between the proportions of alkali metal and the urea or a substituted urea, having more than one replaceable hydrogen, either a monoor a poly-alkali metal ureaor substituted urea may be produced. Thus,

an as example illustrative of this procedure, if two gram atoms of metallic sodium are slowly added to a solution in liquid ammonia of one gram mol. of urea or substituted urea of the mentioned type, I have found that, after removal-of the ammonia, there remains a white reactive solid which has the correct analysis for the corresponding disodium derivative.

Substituent groups which may be present in the substituted ureas which I employ may be alkyl, aryl, aralkyl, acyl, alkylene, or cycloparafe fin radicals. After treatment of a substituted urea with alkali metal according to this invention, the resulting product will contain both the alkali metal and the substituent group or groups.

The following examples are illustrative .of. my invention: i Example 1.-One hundred twenty grams of urea is dissolved in one and'one-half liters of liquid ammonia contained in a two-liter threeneckedfiask fitted with a mercury sealed stirrer. To this solution is added slowly 46 grams of metallic sodium. The reaction proceeds vigorously as the metallic sodium is first added, but slows down as the addition continues. On completionof the addition of the metallic sodium, the liquid ammonia is removed by distillation, and a reactive white solid analyzing 31.2 per cent nitrogen and ,27.85 per cent sodium is obtained. This analysis corresponds satisfactorily with the calculated values for monosodiumurea.

I prefer to separate the monosodium ,urea from the liquid ammonia by filtration, so that the thus recovered liquid ammonia can be reused in subsequent preparations. .2

Example 2.Six grams of urea is dissolved-in one and one-half liters of liquid ammonia contained "in a two-liter three-necked fiask fitted with a mercury sealed stirrer. To this solution is added, slowly 4.6 grams of metallic sodium. The reaction proceeds vigorously as the sodium is first added, but slows down as the addition continues. The solution is allowed to stand: overnight, then one and one-half liters of ammonia are added, and the solution allowed to stand at room temperature for eight hours. The ammonia is allowed to evaporate, leaving a white solid whose analysis shows it to be disodium urea.

A dibenzoyl derivative is obtained by reacting 10.4 grams of disodium urea prepared as described above with 28.1 grams of benzoyl chloride. Thedibenzoyl urea thus prepared after crystallization from alcohol gives white crystals melting at 204205 C., andjupon analysis are showntocontain 10.7 per cent nitrogen, whereslows down as the addition of metallic sodium is continued. The solution is allowed to stand overnight and the mono-sodium phenyl urea recovered by evaporation of the ammonia.

Example 4.To a solution of -76 grams-of thiourea in one and one-half liters of liquid ammonia is added 23 grams of metallic sodium.

The reaction is initially vigorous, but slows down as the addition of metallic sodium is continued.

The solution is allowed to stand overnight and the product recovered by evaporation of the ammonia. The material thus prepared is a pinkish solid which decomposes at 205-215".C.. Example 5.--To fifty grams of benzyl urea dissolved in one and one-half liters of liquid ammonia is added '7 .6 grams of metallic sodium.

The reaction is at first vigorous, but gradually slows downas the addition of metallic sodium is continued. The solution is allowed to stand overnight, and a white solid which is identified as mono-sodium benzyl urea is recovered by evaporation of the ammonia.

Example 6.To 108 grams of oleoyl urea dissolved in liquid ammonia is added slowly 7.6 grams of metallic sodium. The reaction is at first vigorous, ibut graduallyslows down as the addition of metallic sodium is continued. The solution is allowed to stand overnight, and a white solid identified as mono-sodium oleoyl urea is recovered by evaporation of the ammonia.

i Example 7.To 25 grams ofmethyl urea dissolved in one liter of liquid ammonia is added 7.6 grams of metallic sodium. The reaction is at 4.0 first vigorous, but gradually slows down as the addition of metallic sodium is continued. The solution 'is allowed to stand overnight, and a product identified as mono-sodium methyl urea isrecovered by evaporation of the ammonia.

45 Example 8.Sixty grams of urea is dissolved in one and one-half liters of liquid ammonia contained in a two-liter three-necked flask fitted with a mercury sealed stirrer. To this solution is added slowly 39 grams of 'metallic potassium. The reaction is at first vigorous, but slows down toward the end of the addition of the metallic potassium. On'completion of theaddition of the metallic potassium the mixture is filtered. The reactive white solid obtained is shown'by analyses 55 to .be mono-potassium urea. Lithium may be substituted for the potassium of the above example.

I generally prefer to carry out the reaction between the urea or substituted urea and the alkali 60 metal below the boiling point of liquid ammonia,

altho the reaction may, in some cases,'be carried out advantageously at or above the normal boiling point of ammonia. Generally, also, I prefer for reasons of economy to carry out the reaction 65 in a closed system so that the ammonia used as solvent may be recovered for reuse in subsequent anhydrous liquid ammonia,

comprises reacting metallic sodium with urea in anhydrous liquid ammonia.

' 2. A process for producing sodium urea which comprises reacting metallic sodium with urea in and thereafter removing the anhydrous liquid ammonia.

' 3. A process for producing mono sodium urea which comprises reacting metallic sodium and urea in anhydrous liquid ammonia in the proportions of one gram atom of metallic sodium per one gram mol. of urea.

4. A process for producing disodium urea which comprises reacting metallic sodium and urea in anhydrous liquid ammonia in the proportions of two gram atoms of metallic sodium per one gram mol. of urea.

5. A process for producing mono sodium urea which comprises slowly adding metallic sodium to a liquid anhydrous ammonia solution of urea, in

the proportions of about. one gram atom of phenyl urea, in the proportions of about one gram mole of metallic: sodium per gram mole of phenyl urea, and thereafter removing the sodium urea by filtration. I

8. A process for producing alkali metal ureas which comprises reacting in anhydrous liquid ammonia an alkali metal with a urea having at least three amido hydrogen atoms, said urea'being further characterized in that any substituent for the remaining amido hydrogen is a monovalent hydrocarbon radical.

9. A process for producing sodium urea which comprises reacting in. anhydrous liquid ammonia metallic sodium with a urea having at least three amido hydrogen atoms, said urea being further characterized in that any substituent for the remaining amido hydrogen is a monovalent hydrocarbon radical.

10. A process for producing an alkali metal urea which comprises reacting an alkali metal at a pressure inv the range of from atmospheric pressure to about 400 atmospheres with aurea having at least three amido hydrogen atoms, said urea being further characterized in that any substituent for the remaining amido hydrogen is a monovalent hydrocarbon radical.

11. A process for producing monoalkali metal urea which comprises reacting alkali metal and a urea having at least three amido hydrogen atoms in anhydrous liquid ammonia, in the proportions of one gram atom of an alkali metal per gram moi. of the urea, said urea being further characterized in that any substituent for the remaining amido hydrogen is a monovalent hydrocarbon radical.

12. A process for producing dialkali metal urea which comprises reacting alkali metal and a urea having at least three amido hydrogen atoms in maining amide hydrogen is a monovalent hydrocarbon radical.

14. A process for producing disodium urea which comprises reacting metallic sodium and a urea having at least three amido hydrogen atoms 5 in anhydrous liquid ammonia and in the proportions of 2 gram atoms of metallic sodium per gram mol. of the urea, said urea being further characterized in that any substituent for the remaining amido hydrogen is a monovalent hydrocarbon 10 radical.

RALPH A. JACOBSON. 

